A man who claims to have been sleepwalking when he allegedly murdered his 83-year-old father is using a "desperate" defence for his crime.
Jules Lowe's sleeping patterns have been tested by scientists
Jules Lowe, 32, punched, stamped and kicked his father Edward Lowe after a heavy drinking session, Manchester Crown Court was told on Monday.
Mr Lowe, of Walkden, does not deny the attack, but denies murder on the grounds of "automatism".
Prosecutor Richard Marks QC said the sleepwalking defence was "desperate".
Mr Lowe claims he was completely unaware of his actions while sleepwalking.
He told police his only memory of events was drinking into the night with his father at their home.
The victim's body had 90 separate injuries and was left in the drive of their house in Windmill Lane.
"Automatism is a defence which rarely arises in our courts," Richard Marks QC told the court.
"It has been described in one case in the Court of Appeal as a quagmire of law, seldom entered nowadays save for those in desperate need of a defence."
Friends and family of Mr Lowe have told the court of past episodes of his sleepwalking, but he has never before been violent or aggressive at the same time, the court heard.
Mr Lowe, who runs a motorcycle shop, was given a series of scientific tests to examine his sleep patterns while sober and drunk.
Experts say there is a "theoretical possibility" the killing could have taken place while sleepwalking and the fact Mr Lowe might have taken a shower after it, still while sleepwalking.
But there was no recorded case of a person taking a shower and still not waking up, the court heard.
Mr Marks said there had been an "inefficient" attempt at concealing the crime, after Mr Lowe's bloodstained boxer shorts and socks were found next to the bath in the house.
Mr Lowe denies murder on 30 October, 2003. The case was adjourned until Tuesday.